The invention set forth in this specification pertains to new and improved locking structures, and more specifically to locking structures for use in securing a door or similar structure in a closed position with an essentially conventional type of cylindrical lock or lock mechanism.
There are many different types of locks or lock mechanisms which have been known and used. Most frequently they are constructed so as to include a cylindrical housing or barrel which is used to hold and retain lock elements such as, for example, a known tumbler mechanism capable of being actuated by a key or a dial operated combination lock mechanism. When such a mechanism is appropriately actuated a retainer rotatably mounted on the housing is normally moved with respect to the housing so as to accomplish a latching or an unlatching function.
Such conventional locks or lock mechanisms are normally installed in a door or similar structure in such a manner as to permit access to the end of the housing through which a key must be inserted or the end of the housing carrying a dial in a combination type lock. As they are so installed such conventional locks are relatively exposed. In such locations they are apt to be damaged and/or rendered wholly or partially inoperative by ambient influences such as inclement weather. It has long been recognized that the effects of such ambient conditions can be minimized by covering the exposed surfaces of such locks or lock mechanisms with an appropriate barrier or cover plate capable of being easily moved to gain access to a lock itself.
While expedients of this type are unquestionably effective they do not in fact provide a desired degree of protection against what may be considered to be the arsenal of equipment available to many thieves. Many comparatively unsophisticated thieves will utilize brute force type hand tools to render a lock or lock mechanism as described inoperative. When the face of such a mechanism is exposed or reasonably exposed frequently such a mechanism can be disabled and/or disassembled through the application of due force through a sledge hammer to an appropriate chisel-type instrument. Occasionally hand operated drills and other common tools are even utilized on locks and lock mechanisms as described.
However, at the present time thieves frequently do not utilize such essentially laborious methods of overcoming conventional locks and lock mechanisms as described. Thus, for example, it is common place for thieves to utilize commercially available battery operated portable drills with conventional drill bits such as are normally sold for home use in rendering locks or lock mechanisms inoperative. Frequently such individuals will also utilize appropriate cutting torches for this purpose. On occasion conventional lock picking implements will be utilized in breaking into conventional locks or lock mechanisms. In general, however, the use of such picking tools is avoided because of the legal consequences of possessing such tools and/or the possible presumption that any individual owning such tools has used them or intends to use them improperly.
All of these factors have tended to make the use of conventional locks or lock mechanisms as described in the preceding undesirable. It has been recognized that one way of avoiding the relative ease by which such locks or mechanisms can be rendered inoperative would be to utilize specially formed locks or lock mechanisms which are relatively resistant to all of the methods of thievery indicated in the preceding discussion. From an economic standpoint, however, such use of what may be regarded as "better" locks or lock mechanisms is undesirable. In general, the less expensive the lock or lock mechanism used in a particular application is consistent with the degree of protection against undesired entry desired the better.
Hence, it is considered that there is a need for new and improved locking structures for use with conventional relatively inexpensive locks or lock mechanisms as described which will enable such locks or lock mechanisms to be utilized in order to achieve a greater degree of resistance to thievery than it has been previously possible to achieve using these same locks and lock mechanisms. It is considered that this need is particularly significant in connection with doors such as are used on storage containers and the like which are normally located where they are not often inspected.